1. Field of the Invention
The present invention relates to a crusher capable of breaking crushed masses of natural stone or the like efficiently and safely.
2. Description of the Related Art
At quarrying sites, a plurality of holes are drilled in a rock surface for embedding explosives such as dynamite therein, the explosives such as dynamite are embedded in the holes, and the rock is detonated to obtain a multiplicity of crushed masses W of natural stone (see FIGS. 18 and 19). A breaker C is generally used to break the crushed mass W of natural stone into smaller pieces.
The breaker C is mounted at a distal end of an operating boom of a construction vehicle, and by operating the operating boom, the breaker C is brought into contact with the crushed mass W to perform the breaking operation. One crushed mass W at a time is raked out from a big pile of crushed masses W of natural stone and is moved to a flat ground surface or the like. The crushed mass W is set in a stable state suitable for breaking to facilitate the use of the breaker C, and the crushed mass W is broken into a multiplicity of small masses w by the breaker C.
When one crushed mass W at a time is raked out from the pile of crushed masses W, an attachment suitable for raking out the crushed masses w is mounted on the operating boom of another construction vehicle to take out the crushed masses W. Hence, a plurality of construction vehicles including the one equipped with the breaker C are required.
In addition, when the crushed mass W is broken with the breaker C, as shown in FIG. 18, it is necessary to set a chisel c of the breaker C perpendicular to the surface of the crushed mass W. In this manner the crushed mass W is broken into the small masses w by the breaker C.
During the operation of breaking the crushed mass W, there are cases where as the chisel c penetrates the crushed mass W, the direction of the chisel c becomes inevitably offset, or the position of the crushed mass W changes due to the vibration, impact, and the like of the breaker C, causing the direction of percussion of the chisel c of the breaker C to become offset. Accordingly, it is necessary for an operator to constantly correct the direction of the chisel c of the breaker C during the breaking operation.
Furthermore, since the chisel c needs to strike while applying an appropriate load, there is a drawback in that the operation of striking in the horizontal or upward direction cannot be performed in practice.
In the operation in which the rock is detonated with explosives such as dynamite and the multiplicity of crushed masses W in a pile are broken with the breaker C, it is impossible to break the crushed masses W as piled with the breaker C, since the stability of the crushed masses W is very poor.
For this reason, as shown in FIGS. 16 and 17, one crushed mass W at a time is first taken out and raked out from the pile of crushed masses W, and is then moved to a stable flat ground surface or the like. After the crushed mass W is set on that flat ground in a most stable state, the operation of breaking the crushed mass W is effected by means of the breaker C.
To take out the crushed masses W one by one from the pipe, a construction vehicle in which an attachment suitable for raking out the crushed masses W is mounted on its operating boom is required separately from the construction vehicle with the breaker C mounted thereon, as described above. Thus, it is necessary to prepare a plurality of construction vehicles and to deliver them to the site. In addition, a plurality of personnel are required for operating the breaker C and for raking out the crushed masses W. Hence, there are problems in that the cost increases and a long operating time is required.
As described above, in the breaking of the crushed masses W with the breaker C, as shown in FIG. 18, the breaking operation must be performed with the chisel c of the breaker C brought into contact with the crushed mass W perpendicular to the surface thereof. When this operating condition is not met, the crushed mass W cannot be broken efficiently, and it is necessary to make repeated attempts to break the crushed mass W. Hence, a longer operating time is required, thereby increasing the amount of burden imposed upon the operator.
Furthermore, when the crushed mass W is broken, if the condition in which the crushed mass W is set is poor or becomes unstable, the angle at which the chisel c of the breaker C strikes against the crushed mass W deviates from an allowable range, so that the chisel c of the breaker C fails to be brought into contact with the crushed mass W properly. As a result, there are cases where the chisel c strikes at the air, and in a worst case the breaker C may be damaged by the impact exerted by itself, making the breaking operation impossible.
To satisfactorily break the crushed mass W with the breaker C, it is necessary to constantly set the chisel c of the breaker C perpendicular to the surface of the crushed mass W to be broken. In addition, even if the chisel c of the breaker C is at a proper position with respect to the crushed mass W at the time of starting the breaking operation, there are cases where the crushed mass W moves due to the vibration and impact of the breaker C during the breaking operation, and the chisel c is set in an improper state with respect to the crushed mass W. Hence, it is necessary for the operator to constantly confirm the situation during the breaking operation, so that the operation of the breaker C has been difficult and troublesome, and a trained operator has been required for that purpose.
In addition, as shown in FIG. 19, since the force for crushing the crushed mass W is derived from the impact force of the chisel c of the breaker C, the following problems have been encountered: The lives of the breaker and the construction vehicle are extremely short, the scattering of the multiplicity of small masses w to a fairly large area presents an extreme danger to the operator, and large noise is produced when the crushed mass W is crushed by the breaker C.